Gas generating boiler for central heating



Feb 23, 1937.. J Y 2,@?1,578

GAS GENERATING BOILER FOR CENTRAL HEATING Filed Oct. 5, 1935 InventorJulz'enfieiidy A'iftqmqy;

Patented Feb. 23, 1937 UNITED STATES PATENT OFFICE GAS GENERATING BOILERFOR CENTRAL HEATING Julien Bellay, Brussels, Belgium Application October5, 1935, Serial No. 43,762 In Belgium May ll, 1935 Claims.

air admissions distributed over all the height of said chamber.

The gasifying air is introduced in the mass of fuel fed into thefire-box in sufiicient quantity to obtain a maximum production of gas,without however being in excess, so as to insure that the combustion ofthe gas will only take place in the combustion chamber by means of theair admitted to that end.

The gasifying air is generally blown in by means vof an intermittentlyworking electric fan, controlled by a thermostat or any other devicedepending on the water temperature or on the temperature of the premisesto be heated. During the non-operating periods of the fan, which can beof more or less long duration and vary between large limits for adefinite plant, the production of gas diminishes gradually as well asthe temperature in the fire-box or hearth. It is nevertheless necessary,when the fan is set in motion again, that the reaction in the generatoras well as the reaction in the combustion chamber should be startedimmediately or else the fire would probably be extinguished or what ismore serious, an explosion would probably be provoked if the gas is notburnt at its exit from the generator.

This danger is especially encountered when the external temperature isnot very low, which results in long non-operating periods of the fan.

In previous patents, I havedescribed a gasiiying air admission device,acting through a very narrow slit extending along all the depth of thefire-box, so as to realize a practically instant gasifying, at very hightemperature (ash fusion gasifying). This obviates to a large extent, theabove mentioned dangers, without however insuring as yet, full safety.But these dangersexist to a much higher degree with boilers havingfirers 5 gas as soon as given off.

To create this starting point, the atmospheric air admitted in thefire-box, when the fan is stopped, and due to the depression in thefire-box, is compelled to come out at the same point thus realizing atthis point, a zone of fuel of lesser resistance to air passage.

In practice, different manners of carrying this into efiect can beadopted. The discharge aperture of the feeding hopper or funnel extendssub stantially along the back half of the fire box, the front half beingfree.

The fuel falls by gravity, into the fire-box and provides towards thefront part of the fire-box, a natural slope inclined at about 45. Thegasifying air admission pipe extends from the back end 15 of the firebox up to a certain distance from the front end in such a manner thatthe front end of the aperture of this pipe issues at a very slightdistance from the inclined surface of the fuel bed.

In other words, the pipe is arranged in relation 0 to the mass of fuelin,the fire-box in such a manner that at the end of this pipe, thethickness of the fuel layer to be traversed by the air is considerablyless than in any other location, whereby at this point, the resistanceto air passage is very much reduced.

When the fan is stopped, the external air being simply admitted throughthe natural depression in the fire-box, this air will tend to issueat'the point of lesser resistance, and reaction and dis- 0 charge of gaswill always take place at this point; this discharge will be very slightand in practice the gas produced will burn straight away forming a smallflame which plays the part of a pilot to instantaneously light the gasproduced as soon as the fan is set in motion.

The pipe may even be lengthened by a small tube nearly flush with theinclined surface of the fuel slope and producing also a continuous pilotflame.

An example of realization of the invention is shown in the appendeddrawing, in combination to a special kind of boiler also forming part ofthe invention.

In the drawing: 45

Figure 1 is a vertical cross section along line I-I of Figure 2,

Figure 2 is a horizontal cross section along line 11-11 of Figure 1,

Figure 3 is a vertical section along line III-III of Figure 1.

The boiler illustrated, of the mentioned type, with internal fire-boxforming gas generator, with above it a combustion chamber, is double inso far that two complete independent fire-boxes are pro-' to anindependent heating. circuit, both circuits being connected to the maindeparture and arrival pipes of a central heating plant This boiler withtwo independent fire-boxes is an appreciable improvement as regardsusual I boilers; these last named boilers are in fact, generally verydifficult to manage during very cold periods or during transitoryseasons (spring and autumn).

If the boiler is calculated for a maximum temperature or if in otherwords, the boiler is chosen of larger capacity than is normallynecessary, it is very easy to manage the plant during severetemperature, but on the other hand, during normal temperature (springand beginning of autumn) the heating is much too intensive and if it isdesired not to exceed normal temperature there is danger ofextinguishing the fire, in spite of the pilot device according to thisinvention. In

any event, it is very difficult to maintain a normal temperature.

Inversely if the boiler has been chosen so as to allow easy maintenanceof normal temperature during mild temperatures, it will practically beimpossibleto heat up sufficiently during severe temperature. With thedouble fire-box boiler, management is greatly simplified at any timewith use of pilot.

During severe temperature the two fire-boxes or hearths are put intoservice, while during transitional periods, only one of the fire-boxesis put into service, the other one being stopped with its water circuitcut off from the heating conduits.

The boiler body according to the invention is in the form of arectangular parallelepiped I the I by means of the hopper wall 9, theoutside walls of the hopper I 0, bottom of the fire-box and tubulardevice 6.

The hot water leaves through outlet II towards a stop tap not shown,joining to the main outgoing pipe 22 of the central heating plant; thecold water returns at l2, through a tap not shown, connecting to themain common incoming pipe 23. Thus at will, it is possible to cut out ofthe heating circuit one or the other fire-box.

The hopper extends along the whole depth or breadth of the boiler; itpreferably becomes narrower towards the bottom and its bottom I3 isarched in form of a roof. 'The hopper is provided with a slot IQ forfeeding each fire-box by gravity.

This slot (Figure 3) extends nearly along the whole back half of thedepth or breadth of the fireboxes, so as to feed into the fire-boxes amass of fuel i5 which in the direction of the clean out door (in front)automatically attains the inclination of the natural slope.

Gasifying air is blown in by means of a fan not shown; one fan for bothfire-boxes may be provided with a damper controlling each fire-box, orif desired one fan may be provided for each firebox.

I 2,071,678 vided in the body of the boiler, each one belonging In thisexample, the air is blown in through'a pipe I! provided in the wall ofthe hopper so as to insure its cooling and which extends throughout thegreater portion of the depth of the fire-box. In any case, the length ofthe pipe or more exactly the length of the very narrow air exit slit i8is "greater than the fuel feeding slots I4, in such a manner that at thefront end of the slit, the thicknessof the fuel layer to be traversed bythe air is considerably less than at any other point and presents a veryslight resistance to the air passage.

In this way, when the fan is stopped, the air drawn in through the pipeas a result of the depression in the fire-boxes, will tend to issuethrough the point of least resistance. Therefore nearly all this airwill issue at the end of the pipe, insuring at this point maintenance ofa small pilot flame which insures immediate combustion renewal as soonas the fan is set in motion.

As shown in the drawing, a small tube 19 proceeding from the pipe andending nearly flush with the surface of the slope, can also be provided,if desired, said tube being of course cooled is especially of interestwith large air exit aperture pipes.

With this tube l9,'it is possible to avoid the necessity of providing anatural slope, which in fact can be considered as a loss in the use ofthe fire-box cross-section. For instancea slit H extending along thewhole depth of the fire-box could be provided, the tube l9 beingdirected so as to have its outlet near the, upper surface of the mass offuel, for instance at 20 (Figure 1).

The combustion chambers are provided in known manner with tapered slitsor apertures 2| to insure complete combustion of gases and to realize acurtain of flames along the whole height and breadth of the combustionchamber.

Having now fully described my said invention, what I claim and desire tosecure by Letters Patent, is:

1. A generating boiler including a fuel hopper, a fire box receiving thefuel from the hopper by gravity; means for admitting gasifying air tothe fuel, the space in the furnace above the fire box forming acombustion chamber, means for admitting air to support the combustion ofthe gas within the combustion chamber, and means opening through thefuel in the fire box to provide a pilot for the ignition of the gasfollowing interruption of the flow. of gasifying air for any purpose.

2. A gas generating boiler including afuel hopper, a fire box to receivethe fuel from the hopper by gravity, means for admitting gasifying airunder pressure to the fire box within the range of the fuel therein, thespace above the fuel providing a combustion chamber, means for admittingair to support the combustion of the gas within the combustion chamber,and a-pipe communicating with the gasifying air conduit and extendinginto the fuel and terminating adjacent the'surface of the fuel for pilotlight purposes.

3. A gas generating boiler comprising a central fuel-space, an offsetfire box and combustion chamber divided from the fuel space, means fordelivering fuel from the fuel space to the fire box, said means having alength less than the length of the fire box to cause the delivered fuelto present an area of gradually decreasing depth toward the front, meansfor feeding gasifying air into the fuel, and means for providing apilot, said pilot providing means opening adjacent the surface of thefuel in its portion of decreased height.

4. A gas generating boiler including a fuel space, a combined fire boxand combustion chamber, a wall separating the fuel space and combinedfire box and combustion chamber, means for delivering fuel through anopening in said wall from the fuel space to the fire box, said openingbeing of less length than the length ofthe fire box to compel the fuelas delivered to assume a position of gradually decreasing depth from thefront of the opening to the front of the combined fire box andcombustion chamber, means for admitting gasifying air to the fuel boxbelow the fuel delivery opening, and means for admitting air to thecombustion chamber above the fire box.

5. A construction as defined in claim 4, wherein the means for admittinggasifying air' to the fuel of the fire box includes a conduit openingthrough the wall between the combustion chamber and fuel space in theform of a narrow elongated slot.

6. A construction as defined in claim 4, wherein the means for admittinggasifying air to the fire box includes a conduit communicating with anarrow elongated slot in said wall opening to the fire box, and a pilotpipe communicating with said conduit and extending substantially throughthe fuel in that portion of the fuel which is of decreased height.

7. A construction as defined in claim 4, wherein the heated air from thecombustion chamber is directed into a tortuous path within the furnacefor heating purposes.

8. A gas generating boiler including downwardly converging wallsdefining a fuel space, a chamber beyond each wall relative to the fuelspace defining a fire box and combustion chamber, a water compartmentbeyond the wall, fiue pipes in said water compartment open at the upperend to the combustion chamber and at the lower end to a common outlet,an opening in each of said walls for delivering fuel from the fuel spacebetween the walls to the respective fire boxes, a gasifying air conduitleading from the source of supply through each of said walls into thefire box, and combustion air conduits opening. into the combustionchamber and supported by a wall of the heating compartment.

9. A construction as defined in claim 8, wherein the space between theconverging walls is provided with a curved bridge piece leading to thefuel openings in the walls and serving to support the fuel in the fuelspace, the conduits for delivering the gasifying air to the fire boxesbeing supported in the space below the bridge piece.

10. A construction as defined in claim 8, wherein the combustion airconduits opening into the combustion chamber are arranged in staggeredrelation throughout the vertical length of the combustion chamber andare supported by a wall of the heating compartment.

J ULIEN BELLAY.

